Message-register system



June 9, 1925. 1,541,356

F. S. IRVINE MESSAGE REGISTER SYSTEM Filed Nov. 24. 1922 5 Sheets-Sheet1 Myen/af: Fran/r 5. /r|//'/1e.

by WA 173/.

June 9, 1925. 1,541,356

F. s. IRVINE MESSAGE REGI STER SYSTEM Filed Nov. 24, 1922' 5Sheets-Sheet 2 Q8 Y u .2

Arty

June 9, 1925.

F. S. IRVINE MESSAGE REGISTER SYSTEM w 6 w M m M m a 29 cw 9 25:2 m w 2m n 5 W k mrn N i 2 mi a y 0 M I v m w m June 9, 1925.

F. S. IRVINE MESSAGE REGISTER SYSTEM Filed Nov. 24, 1922 5 Sheets-Sheet4 June 9, 1925. 1,541,356

F. S. IRVINE MESSAGE REGISTER SYSTEM Filed Nov. 24, 1922 5 Sheets-Sheet5 A/f'y Patented dune W25.

cam-c start e Z P-Artur civics.

FRANK s; IRVINE, ornun'rineron, NEW. YORK. Assienon 'ro wns'rnannnncrnic COMPANY, moonrona'rnn, or new YORK,- my a ccnrona'r on or newYORK.

stresses-REGI TER. sysrnm.

Application filed November 24, 1122. Serial No. 602,9 18,

To all whom it may conceit;

die it known that I, FRANK S. IRVINE, a

citizen of the United States, residing at.

Huntington, in. the county of Sufiolk and Stateof New York, haveinventedrcrtain new and useful Improvements in Message- RegisterSystems, of whichthe following is a fulL-clear, concise, and exactdescription.

This invention relates to message register systems for telephonevexchanges and more particularly to message register systems for use intelephone exchanges employing party line-working wherein each of thestationsot' the party line is provided at the central .of- .fice with amessage register for registering calls.

An object of the invention is to provide an improved circuit arrangementfor use in systems of this nature for selectively associating with thecalling station of a party line the message register individual theretoand for subsequently operating said register.

Another object of the invention is an inn proved arrangement forpieventing the re istration of calls upon the party lines whio are in anunstandard' condition. i

To attain the objects of the invention, each station of the party lineisprovided with a certain test condition and the first selector ingwhich station of the party line is'calling.

The testing means controls the actuation of I the nduction coil when thereceiver ed the a switching device associated withlthe calling line,which in turn controls the inclusion of the message registercorrespondingto the I .iground to the tip conductor of .the 11118 Thesubstation on callingdine in the message register circuit.

This organization provides an improvement 1 (nor a circuit arrangementshown in a patent to l). M. Taggart aiid QF. J. Scuddel', 1,513,351,issued Oct. 28, 1924, wherein the switching device is not individual tothe callfline,-tl etesting means operates at this time,

prevents the charging ofthe-call and causes the operation of an alarmdevice.

i The invention may be more-readily understood hyi'eference to-thefollowing descrip tion considered in connection witlithe ac;'coinpanying drawings, in which Fig. 1- shows one of agroup of two-partylines for use in a full mechanical office. Figs. 2, 3 and 5, whenv takentogethenshow the circuits of a line finder having access to thesubscribers line shown in Fig. 1-, .the circuits of a dis trict selectorswitch, a sender tinder and so much oi'an office sender as is necessaryfor an understanding of the invention; Fig. 4: in

- eludes a schematic showing of an incoming selector switch, a finalselector switch and a subscrihers line to which the final selector iswitch has access. I The several figures of the drawing should bearranged with Fig. 1 to the left, FigsjQ, 3 and 4 in consecutive order'switchhook, whereas at thei other substation; the-call bell is at alltimes connected from through? a condenser. called line C, 4, is of theusual type. 4

The calling line terminates in a line finder switch of the well-knownpower driven paneltype. The brushes of the line finder are connected tothe circuit of a district selector switch. Associated with each of thesubstations A and B, connected to the calling line, is a messageregister. Associated with the calling line is a cut-0d re lay, whichcontrols the extension of a common operating circuit extending through a.hrush of the-line finder switch to the message registers.

district selector, incoming selector ice and final selector switchesshown in Figs. 3 and 4 are of the general t pe shown and described inthe patent to raft and Reynolds, 1,123,696, issued January 5, 1915. Eachof. these switches has a vertically dis posed switch shaft provided withfive sets of brushes, each brush set having access to a bank ofone-hundred terminals. For driw ing the switch shaft upwardly, anupdrive magnet is provided, which, when energized, presses the switchshaft against a constant- 1 rotating power drum, and for restoring theswitch shaft to normal position, a downdrive magnet is provided, which,when energized, presses the switch shaft against a second constantlydriven drum. For determining the particular set of brushes on the switchshaft to be employed, a tripping spindle is provided as described in thepatent hereinbefore referred to. The circuits of the incomingselectorswitch and the final selector switch may be of the typedescribed in the patent to D. M. Taggart, et al., hereinabove mentioned.

The steering switch RS, shown in Fig. 2, and the sender finder switchFS, shown in Fig. 3, are of the well-known step-by-step type, the wipersof which are advanced by a stepping magnet. The switch RS functionsduring a complete half revolution and upon the termination of aconnection left with its wipers in normal condition for serving on a newcall. The wipers of finder switch FS have no normal" contacts, thewipers resting in contact with the bank ter minals last employed by theswitch when the switch is not being employed.

The ofiice sender has been only partially disclosed in Fig. 5, only suchportions of the sender being disclosed as are considered necessary foran understanding of this invention. The circuits of a complete otficesender are disclosed in Patent No. 1,395,977 to F. A. Stearn and F. J.Scudder, of November 1, 1921.

For controlling the circuits associated withthe several selectorswitches and the circuits of the ofiice sender, auxiliary switches areprovided. These switches may be of the type described in the patent toReynolds, et al., 1,127,808, issued February 9, 1915, and known in theart as sequence switches. Each sequence switch comprises a rotatableshaft driven from a constantly operating source of power through amagnetic clutch member and carries a plurality of circuit closing camswhich at difierent radial ositions of the shaft, cause the closure 0 aplurality of contacts. The cam contacts associated with each sequenceswitch are closed only in the positions indicated by the numerals, withthe exception of the master contacts 301, 401 and 551 associated,respectively, with the switches 300, 400 and 550, these latter contactsbeing opened in positions indicated by the numerals appearing adjacentsuch contacts and closed in all other positions.

The different pieces of apparatus -employed in the system having nowbeen briefly described, it is thought that a clearer understanding ofthe invention may be had from a description of the method ofestablishing a. call. It will first be assumed that the subscriber atsubstation A desires connection with a line at substation and that thedirectory number of the desired subscriber is LISpenard 9532.

Upon removal of the receiver from the switchhook at the station A, acircuit is established for line relay 102 over a path including groundedbattery, winding of re left-hand armature of relay 103 and ground.

The line relay 102 becomes energized in this circuit and completes acircuit for the group relay 104, common to all lines in the A sub--group of this particular brush group, to ground at the inner armatureand contact of relay 102. Relay 104 becomes energized and completes acircuit from ground through its armature and contact, contact andarmature of relay 105, left-hand armature and back contact of relay 106and lefthand winding of relay 107 to grounded battery. Relay 107operates in this circuit and in attracting its right-hand armaturecompletes a locking circuit for itself and an energizing circuit forrelay 218, said circuit extending over a path including groundedbattery, winding of relay 218, conductor 124, right-hand armature, frontcontact and right-hand winding of relay 107 to ground. Relay 107, inattracting its outer left-hand armature completes an obvious circuit foroperating the tripping magnet 213. Triplng magnet 213 rotates itstripping spin (lo 212. The tripping spindle in its rotated positionprepares for the tripping of the set of brushes on the particular finderswitch that is started in operation to find the calling line.

Relay 218, in operating, completes a circuit for relay 299 over a pathincluding grounded battery, right-hand winding of relay 299, backcontact and outer right-hand armature of relay 298. back contact andright-hand armature of relay 2941. and contact and armature of relay 218to ground. Relay 299, in operating, locks over a path including groundedbattery, rigl'it-hand winding, front contact and inner left-handarmature and left-hand winding of relay 299, and ground at the backcontact and armature of relay 214. Relay 299 in attracting its outerlett-hand armature completes a circuit for the updrive power magnet 216over a path including segment 295 tact 287 is momentarily closed and acircuit is established from ground over said contact, conductor 1525,inner left-hand armature and front contact of relay 107 and the windingof relay 106 to grounded battery. Relay 1.06 attracts its armatures andlocks in a circuit including battery, windin front contact and left-handarmature of relay 106. armature and back contact of relay 105 and groundat the contacts of relay 104. Relay 106, in attracting its right-handarmature closes a circuit for the right-hand winding of relay 105. Thiswinding is wound so that suflicient flux is not produced to cause theoperation of relay 105. The right-hand winding of relay 103, however,maintains the armature of said relay attracted when it has been operatedby the left-hand winding. Relay 299, in attracting its outer left-handarn'iature also completes a circuit for relay 325, said circuitincluding ground at brush segment 205, front contact and outer left-handarmature of relay 299, inner righthand armature and. back contact oirelay 296, and grounded battery at the left-hand winding of relay 232,5.Relay operates in. this circuit and lurks over a path including battery,right-hand winding ofrelay 325, left-hand contact of sequence switchspring 308 (1 +10), outer right-hand armature and front contact of reay3:35 and ground at the wiper 1' 1 ot' the sender finder FS provided thearm 301 is star ding on the test terminal of a busy sender. Theoperation of the sender finder FS ill be described hereafter. Relay 325in operaring completes an obvious circuit through its inner left-handcontacts for operating rela 394.

As the brushes 204 to 207 inclusive of the switch LF- are movedupwardly, brush 281 comes into engagement with segment 284 and comphtesa a circuit for relays 294a and 200, said circuit extending over apath fron'i ground through brush 281. segment 284: and thence in'iarallcl, one path extending through the right-hand alternate contactsof relay 200. inner right-hand normal ((lIlizlClS oi relay "ll-lb.left-hand normal contacts and winding of relay 294i, and the other pathextending through the winding of relay 206 to grounded battery. Relay2294, in operating. opens at its right-hand contacts the originalenergizing circuit for relay 205), but relay 29!) remains energizedthrough its locking circuit. Relay 2%. in operating. completes acircuit. for the energization of relay 2028, said circuit inrluiilinggrounded battery, right-hand winding of relay 2295 and ground at theinner left-hand contacts of relay 290. Relay 208, in operating, locksover a path including ground through the contacts of relay 218,left-hand contact and winding of relay 298 and grounded battery at theleft-hand contacts of relay 398. Relay'296 in operating also completes acircuit for the energization of relay 292 and the stepping magnet 303 ofthe switch F S, said circuit extending from ground, through the lowerleft-hand contact of se uence switch spring 389 (Ll-1 A), outer rigit-hand con tacts of relay 296, inner right-hand alternate contacts ofrelay 825 and thence in parallel, one path extending through thecontacts and winding of stepping magnet 303 to grounded battery and theother path extending through the right-hand Winding of relay 292 togrounded battery. Relay 296, in operating, also completes a circuit forthe energization of relay 390, said circuit extending over a path fromgrounded battery, through the right-hand winding of relay 2500,intermediate right-hand contacts of relay 2.00 and upper lcft-handcontact of sequence switch spring 314 (LI-10 A), to ground. As the linefinder brush shaft is moved upwardly, brush 286 engages segment Q93causing a shunt to be placed around the winding of relay 107 whereuponsaid relay 107 releases. 286 passes out of engagement with segment 203,relay 218 releases.

When the brush shaftof the line finder arrives at the terminal of thecalling line, relay 214 operates over a path extending from ground,through the outer right-hand contacts oi relay 270, winding of relay21%, upper left-hand contact of sequence switch spring 380 (1 lowerright-hand contact of said spring (1), brush 207, contact 203, outerright-hand alternate contacts of relay 102 and left-hand winding ofrelay 105 to grounded battery. Immediately thereafter or when the brush280 centers upon the contact of the segment 283, corresponding to thecalling line, the locking circuit for relay 299 is opened whereupon saidrelay releases and opens at its outer left-hand contacts the circuit forthe updrive magnet 216 whereulion the upward movement of the brushes isstopped. Relay 308 then operates over a path extending from groundedhattery. tin-(nigh the left-hand normal contacts of relay 2T0, left-handalternate contacts of relay 1500. upper right-hand Contact of se quenceswitch spring 2301 (1+15), winding of relay 398. outer left-handcontacts of relay 296. outer right-hand normal contacts oi? rcla-y129$), segment 284: and brush 281 to ground. The relay 39a, inoperating, completes a circuit for the energization of the cut-off relay10 1 of the calling line, said circuit extending over path from groundthrijiugh the winding of relay 103, contact \V hen the brush 202, brush206, resistance 388 and left-hand alternate contacts of relay 398 togrounded battery. Relay 103, in operating, disconnects the line relay102 from the calling line.

l/Vith sequence switch 300 in position 1, stepping magnet 303,associated with the switch FS, is energized as previouslyvdescribed andrelay 325 is locked up to ground at a busy contact of switch FS providedwiper 391 of the switch FS is resting on the contacts of a busy sender.So long, however, as the test wiper 391 of the switch FS encounterscontacts upon which busy ground potential exists, the stepping magnet303 will advance the wipers of the switch until an idle sender is found,when the wiper 391 will find no ground on the contacts of the idlesender and the relay 325 will thereupon become deenergized. Relay 325,in retracting its inner right-hand armature, opens the circuitpreviously traced for relay 292 and stepping magnet 303, and inretracting its inner left-hand armature opens the circuit for relay 394,whereupon said relays 292 and 394 release. As soon as, relay 292releases, a circuit for operating relay 365 is com pleted over a pathextending from grounded battery, through the right and left-handwindings of relay 365, lower right and lefthand contacts of sequenceswitch spring 305 (1), inner right-hand contacts of relay 398,right-hand contacts of relay 292, segment 295 and brush 282 to ground.If the sequence switch 300 remains in position 1 longer than a certaininterval, an alarm signal is actuated. Relay 327 also operates over acircuit extending from grounded battery, through the right-hand windingof relay 327, upper left-hand contact-of sequence switch 304 (1), upperright-hand contact of sequence switch contact 305 (1+9), lower left-handcontact of said spring (1), inner right-hand contacts of relay 398,right-hand contacts of relay 292, segment 295 and brush 282 to ground.Sequence switch magnet 300 then operates over a path extending fromgrounded battery, through winding of magnet 300, lower righthandcontacts of sequence switch spring 306 (1), front contact and outerright-hand armature of relay 327 and upper right-hand contar t ofsequence switch spring 307 (1+5) to ground. driving sequence switch 300from position 1 into position 2. As sequence switch 300 moves out ofposition 1, the circuits for relays 327 and 365 are opened and theserelays release. If, at the time relay is energized, the wipers of switchFS are standing upon contacts which are connected to circuits extendingto an idle ofiice sender, relay 325 does not lock up over the Circuitpreviously traced and the circuit previously traced through steppingmagnet 303 is immediately opened at the inner righthand armature andfront contact of relay menses 325a prevent the advance of the wipers ofthe switch FS.

In position 2 of sequence switch 300, relay 325 operates over a pathincluding a grounded battery and ground at the lower right-hand contactsof spring 308 (2+13). Relay 39 1 then operates over' an obvious circuit.With the sequence switch 300 in position 2, relay 510, associated withthe selected ofiice sender, is operated over a path extending fromgrounded battery, through the right-hand winding of relay 510, wiper 391of the switch FS, outer right-hand contacts of relay 325 and lowerright-hand contacts of spring 308 (2+13), to ground. Relay 510 energizesin this circuit and causes the advancement of the time measuring switch,not shown, associated with the ofiice sender in the manner fully setforth in the patent of Stearn and Scudder, hereinhefore re ferred to,which time measuring switch upon leaving normal position closes theoff-non mal contact 511. The test contact upon which wiper 391 is nowresting is marked with a busy ground potential over a circuit which maybe traced from off-normal contact 511, through the left-hand winding ofdifferential relay 510, and thence to the wiper 391, whereby the senderis marked as busy until the office sender has been restored to normalcondition either following the abandonment of the call or thetermination of the functioning of the office sender.

lVith relays 510 and 394 energized, an impulsing circuit is nowestablished from the conductors of the calling line through the windingof the sender pulsing relay for enabling the calling subscriber to setthe registers (not shown) associated with the sender in accordance withthe designation of the desired line. This circuit may be traced fromground, through the armature and front contact of relay 510, conductor513, contact 386 and wiper 375 of the sender tinder FS, inner left-handcontacts of relay 394, lower right-hand contact of sequence switchspring 313 (2+9 conductor 117, inner left-hand contacts of relay 292,brush 205 and contact 201 of the switch LF, thence through the impulsecontacts 130 of the calling subscribers dial S. through the subscriberssubstation circuit. contact 200 and brush 201 of the switch Llintermediate 1e ft-haud contacts of relay 29:3. conductor 116. lowerleft-hand contact of sequence switch spring 312 (2-l-9 wiper 317 andcontact 385 of switch FS. thence through the winding of pulsing relay512 to battery.

The calling subscriber now receives a dialing tone over this circuit inthe manner set forth in the aforesaid patent of Steam ct al. and thenproceeds to dial the number of the desired line. Under the assumpt onthat the subscriber desires a connection with thence Ill) menace asubscribers line C which line is listed in the directory as LISpenard9532, the subscriber proceeds to dial the three letters L I Scorresponding to the designation of the ofiice in which the desired line.is located and then dials the four digits representing the number ofthe line, which number, as assumed, is 9532. The three letters whichrepresent the district code will cause the setting of code registers(not shown) associated with the office sender which, in turn, controlthe operation of the sender to control the setting of the dstrictselector switch 350 and the setting of the sequence switch of thedistrict selector for determining the proper talking path through therepeating coil 336 associated with the district selector. Thetransmission of the impulses corresponding to the number of the desiredsubscribers line 9532 causes the setting of the numerical registersassociated with the sender to control the sender to govern the settingof the incoming selector switch 450 and of the final selector switch 490for ex tending the connection to the desired line in the selecteddistrict.

Following the setting of the code registers of the sender. the sequenceswitch 550 associated with the ofiice sender is driven into position 2in the manner set forth in the aforesaid patent of Steam, et al., forestablishing a fundamental circuit extending from the office senderthrough the winding of relay 327 of the district selector switch forcontrolling the setting of the district selector. Since at this time thesequence switch 300 of the district selector is in position 2. thefundamental circuit may be traced from grounded battery, through theleft-hand winding of relay 327, the lower left-hand contact of sequenceswitch spring 310 (2), upper left-hand contact of said spring (2+5),outer left-hand contacts of relay-325, wiper 350 and contact 383 ofswitch FS, upper and lower contact-s of sequence switch spring 519 (2),armature and back contact of the 0 countin relay 520, the windings ofthe polarized relay 52-2, the windings of sender stepping relay 521 andthence to ground through the lower left-hand and right-hand contacts ofse quence switch cam 523 and resistance element 524.

Relay 327 of the district selector switch and stepping relay 521 of theoflice sender are energized in this circuit. Relay 521, upon energizing,establishes a circuit in the well-known manner for an upper counting.

relay of the group of counting relays associated with the sendercorresponding to the setting of the code registers and relay 327 closesa circuit for driving sequence switch 300 f the district selector out ofposition 2 and into position 3. This circuit extends from groundedbattery, through the magnet winding of sequence switch 300,

lower right-hand contact of sequence switch right-hand contacts of relay394, lower lefthand contact of sequence switch spring 333 (2+9), wiper397 and contact 393 of switch FS, right-hand contacts of relay 537 andresistance 538 to ground. Relay 365 0 rates in this circuit but performsno usefu function at this time. sequence switch 300 in position 3, theinitial energizing circuit of relay 327 is opened at the lower left-handcontact of sequence switch spring 310, but relay 327 is maintainedenergized over the fundamental circuit by a new circuit extendin fromgrounded battery, through its leftand winding, its left-hand armatureand front contact and thence through the lower right-hand contact ofsequence switch cam 310 (1+5) and over the fundamental circuit aspreviously traced. A circuit is now closed for the updrive magnet 338 ofthe district selector, which circuit extends from grounded battery,through the winding of magnet 338, the upper righthand contact ofsequence switch spring 309 (3). the lower left-hand contact of saidspring (3+18), front contact and outer right-hand armature of relay 327,upper right-hand contact of sequence switch sprmg 307 (1+5) to ground.Magnet 338, upon energizing, presses the depending portion of the switchshaft (not shown) against the constantly rotating updrive drum (notshown), thereby causing the updrive movement of the switch shaft.

As the switch shaft at the district selector switch moves upwardly andapproaches its first brush tripping position, brush 341 engages thefirst metallic portion of the commutator segment 342 and a circuit isclosed as follows in shunt of the windings of the sender stepping relay521 which may be traced from grounded battery, through the left-handwinding, front contact and lefthand armature of relay 327, the lowerrighthand contact of sequence switch spring 310 (1+5), upper lefthandcontact of sequence switch spring 311 (2 +3), conductor 343, commutatorsegment 342, brush 341, conductor 344, lower right-hand contact ofsequence switch spring 314 (8+6), to ground. Relay 327 is maintainedenergized over this shunt circuit but relay 521 being shunteddeenergizes causing in the well-known manner the energization of thelower counting relay corresponding to the previously energized uppercounting relay. As the switch shaft With the district selector continuedits upward movement, brush 341 poition of the. segment 342 and the shuntaround the windings of sendcr stepping relay 521 is removed, whereuponthe sender stepping relay again energizes. in this manner, during theupward movement of the switch shaft. the stepping relay 521 of theoflice sender is intermittently energized and dc energized causingtllGiSllCCGSSlVB energization of the counting relays associated with thesender. If it be assumed that the No. 2 counting relay was energizedupon the initial energization of: sender stepping relay 521, then, whenthe switch shaft of the district selector has advanced to such aposition as to position the third set of brushes can ried thereby inposition to be tripped, the No. 0 counting relay 520 will be energizedin series with the No. 0 counting relay 525 and will open the previouslytraced fundamental cireuit at its armature and back contact. Countingrelay 520 is also instrumental at this time in causing the advancementof the sender sequence switch 550 out of position 2 and into position 4;Upon leaving) position 2, all counting relays which have een energizedand looked upgover the circuit extending from the sequence switchcontact 526, become deenergized.

As soon following the opening of the fundamental circuit by the No. 0counting relay 520 as the brush 341 engages the next insulating portionof the commutator segment 342, relay 327 becomes deenergized and closesa circuit for driving district selector sequence switch 300 out ofposition 3 and.

"ith sequence switch 330 of the district selector in position 4 and thesender sequence switch 550 in position 4, the fundamental circuitpreviously traced is again established and relays 327 and 521 againenergize. Relay 521 now establishes acircuit through one of the uppercounting; rclays in accordance wilhthe setting of the code registers andrelay 327 establishes a, circuit for driving sequence switch 30(1 out ofposition 4 and into position 5, this circuit extending from groundedbattery, through the magnet winding of sequence switch 300, the lowerright-hand contact of sequence switch spring 306 (4), front colitact andouter right-hand armature of remamas W V lay 327 and right-hand contactof sequence moves into engagement with an insulating.

switch spring 307 (1+5) to ground. Upon leaving position 4, sequenceswitch 3()() opens the initial energizing circuit. of relay 327 butrelay 327 is DOW maintained energized over the fundamental circuitthrough the lower right-hand contact of sequence switch spring 310 (1+5)and the left-hand armature; and front contact and left-hand winding ofrelay 327.

Upon reaching position5, the circuit previously traced through thewinding of updrive magnet 338 is again established through the upperright-hand contact of sequence switch spring 309 (5) {and in the mannerpreviously described the switch shaft is again drgiven upwardly. Sinceat this time; however, the tripping spindle (not shown) has'been rotatedby the tripping magnet 346 which was energized in position 4 ofthesequenoe switch over a circuit extending from grounded battery,through the winding of tripping magnet 346 and to ground through theupper righthand contacts of sequence switch spring 308, the third set ofbrushes is now tripped through the initial upward movement of the switchshaft and during the continued upward: movement of the switch shaft thetripped set of brushes travel over the con- (acts of the bank with,which they are associated. The remaining four sets of brushes on theswitch shaft are not tripped at this time and are, therefore,functionless.

As the switch shaft continues its upward movement and the tripped set ofbrushes approaches the first set of terminals in the first group oftrunks to which the set of brushes has access, the brush 347 engages thefirst metallic portion of commutator segment 348 and a circuit is closedin shunt of the windings of the sender stepping relay 521, which shuntcircuit may be traced from grounded battery, through the left-handwinding, left-hand armature and'front con tact of relay 327, the lowerright-hand contact of sequence switch spring 310 (1+5). upper right-handcontact of said spring (4 44-5), conductor 349,5egment 348, brush 347.conductor 344. lower right-hand contact of sequence switch spring 314(3+6). to ground. Relay 327 is held energized over this circuit, butsender stepping relay 521 deenergizes, causing, upon itsdeencrgiza-tion, the energization of a lower counting relaycorresponding to the upper counting relay whiclrwas energized upon theinitial energization of relay 521. 7

1 As the brush shaft continues in its upward movement, brush 347 engagesan insulating portion of segment. 348 and the. shunt around the windingof sender stepping relay 521 is opened, whereupon relay 521 reenergizescausing the energization of the next succeeding upper counting relay.

In this manner during the continued advancement of the switch shaft, thesteppin; relay 521 of the sender is intermittcntly energized anddeenergized to encrgize and lock up successive lower and upper countingrelays. If it be assumed that the subscriber has set the code registersin such a manner as to cause the No. 0 lower counting relay 525 tobecome energized upon the initial encrgization of relay 521, then uponthe first deenergization of relay 521, the No. 0' counting relay 520will become energized in series with relay 525, thereby opening thefundamental circuit and causing the advance of the sender sequenceswitch 550 from'position i into position 6. At this time the selectedset of brushes of the district. selextor switch will be positioned uponthe lowerinostset of terminals of the first group of its associatedbank. Upon the advance of sequence switch 550 out of position 4. thlocking circuit of counting relays. 5201 and is opened at sequenceswitch spring 526.

As soon following the opening of the fundamental circuit by the No. 0counting relay T20 as the brush 347 engages the next insulating portionof commutator 348, relay 327 becomes deenergized, opening at the frontcontact of its inner right-hand armature, the previously traced circuitof the up drive magnet 338 to arrest the upwardmovement of the switchshaft, and closing at the back contact of its outer right-hand armaturethe previously traced circuit for advancing sequence switch 300 out ofposition 5 and into position 6.

At the time sequence switch 300 moved into position 5. a circuit wasestablished for advancing the steering switch RS from position 1 toposition 2. This circuit may be traced from grounded battery. throughwiper 247. contact 227 winding of stepping magnet 230, wiper 231,contact 232. conduct-or 233 and thence to ground through the upperleft-hand contact of sequence switch spring 389. Stepping magnet 230energizes in this circuit and is held encrgized until sequence switch300 leaves posi tion 6 4 when magnet 230 deenergizes to advance thewipers of switch RS to the second position contacts.

\Vith sequence switch 300 in position 6, a circuit is established forrelay 327 which may be traced from grounded battery through itsright-hand winding, left-hand contact of sequence switch spring 304 (6+6 upper right-hand contact of sequence switch spring 305 (1+9), lowerleft-hand contact of said spring (6+7), inner righthand, contacts ofrelay 398, right-hand contacts of relay 292, segment 295 and brush toground. Relay 327, upon energizing, closes a circuit for drivingsequence switch 300 out of position 6 and into position 7, This circuitmay be traced from grounded battery, through the magnet winding ofsequence switch 300, lower right-hand contact of sequence switch spring306 ((3), outer right-hand contacts of relay 327, upper left-handcontacts of sequence switch spring 307 (6+7), right-hand alternatecontacts of relay 390 and lower left-hand contact of sequence switchspring 314 (l +18 to ground.

As soon as sequence switch 300' leaves position (3 the initialenergizing circuit of relay 327 is opened at sequence switch spring 304,but if the first. trunk in the group of trunks upon which the brushes352 and 353 are now standing is busy, a ground potential exists on thetest terminal 354 and relay 327 is maintained energized over a circuitext-ending from grounded battery, through its left-hand winding,armature and front contact, lower left-hand contact of sequence switchspring 315 (6%+8),'lower right-hand contact of said spring (1+14), innerright-hand contacts of relay 327, righthand contacts of sequence switchspring 382 (6+7), brush 351) and terminal 35%, and when sequence switch30!) reaches position 7, a circuit is established for the updrive magnet338. The circuit of updrive magnet 338 may be traced from groundedbattery, through the winding of this magnet, upper right-hand contact ofswitch spring 309 (7), lower left-hand contacts of said spring (3+ 18),outer right-hand alternate contacts of relay 327, and upper right-handcontact of sequence switch spring 307 to ground. The updrive magnet 338,upon energizing, drives the brushes upwardly in search of an idle trunkin the selected group. So long as the test brush 350 encounters theterminals of 'busy trunks, relay 327 remains locked.

no ground potential exists on the test terminal 357 and relay 327deenergizes as soon as the brushes have been properly centered on thebank terminals 351, 352 and Until the brushes are centered, relay 327 ismaintained looked over a circuit extending through its right-handwinding, the upper right-hand contact of sequence switch spring 304 (7),segment 359, brush 36(), upper lefthand contact of sequence switchspring 309 (7), lower left-hand contact of said spring (ll-+18), outerright-hand alternate contacts of relay 327, and upper right-handcontacts of sequence switch spring 307 (G 9) to ground. Relay 327, upondeenergizing, opens the circuit of updrive magnet 338, thereby arrestingthe brushes 351, 352 and 353 upon the terminals 355, 356 and 357 of thetrunk line extending to the district of the exchange in which thedesired Jun line terminates. Relay 327, upon deenergizlay 365 isoperated over the path previously traced, including ground at resistance538, and grounded battery at right-hand winding of relay In position 8of sequence switch 300, relay 327 is again operated over a circuitextending from grounded battery, through the right-hand winding of relay327, left contact of sequence switch spring 304, upper left-hand contactof sequence switch spring 305 (1+9), upper left hand contact of saidspring (84-16%), and outer right-hand contacts of relay 365 to ground.Relay 327, upon energizing, closes a circuit through its outerright-hand armature and front contact for driving sequence switch 300out of position 8 and into position This circuit extends from groundedbattery, through the magnet winding of sequence switch 300, lowerrighthand contact of sequence switch spring 306, outer righthandcontacts of relay 327 and upper righthand contact of sequence switchspring 307 to ground.

In position 9 of sequence switch 300, relay 327 is held energized overthe circuit just traced until selection beyond the district selector 350has been completed. In position 9 of sequence switch 350, thefundamental circuit is extended from the ofiice sender through contactsof se uence switch springs 318 and 319 of the istrict selector to theline relay 421 of the incoming selector switch 450. The fundamentalcircuit may be traced from grounded battery, through the left-handwinding of relay 421, lower contactof sequence switch spring 402 (1+10),upper contact of said spring (1), resistance 424, lower contact ofspring 403 (1+10), conductor 419, terminal 355, brush 351, upperright-hand contact of spring 318 (9+14), lower left-hand contact of saidspring (9), outer left-hand contacts of relay 325, wiper 350 and contact383, upper and lower contacts of spring 519 (6), contacts of thecounting relay 520, windings of relays 522 and 521, lower and uppercontacts of spring 523 (6), wiper 339 and its associated contact, lowerright'hand contact of spring 319 (9), upper right-hand contact of saidspring (9+14), brush 352, terminal 356, conductor 420, upper contact ofspring 404 (1+10), resistance 425 and lower contact of spring 405 toground. Relays 521 and 421 energize in this circuit. In a manner fullydescribed in the Taggart, etal. patent hereinbefore mentioned, theincoming selector switch is then set after which the final selectorswitch is set in its tens and units selection movements. During theunits selection movement of the final selector switch, steering switchRS is in position 2, sequence switch 300 is in position 9, sequenceswitch 400. will be in position 8 and relay 421 of the incoming selectorswitch will be energized in the manner described in the Taggart et al.patent.

Following the units selection movement of the final selector switch andduring the testing operation of the switch, the circuit of relay 421 isopened causing the deenergization of this relay. Relay 421, upon deenergizing, closes a circuit for driving sequence switch 400 out ofposition 8 and into position 9. This circuit may be traced fromtgrounded battery, through the windin 0 sequence switch magnet 400,upper le -hand contact of sequence switch spring 406 (8), and thence toground at the inner left-hand armature and back contact of relay 421.WVith sequence switch 400 in position 9, relay 421 is again connectedinto the fundamental circuit extending through the windings of thesender stepping relay 521 and the windings of overflow relay 522, butsince at this time the winding of relay 421 is connected to the ringconductor of the fundamental circuit rather than to the tip conductor asdescribed in the Taggart et al. application, current flowing in thefundamental circuit now flows in a direction reverse to that directionin which it originally flowed. The circuit of relay 421 may be tracedfrom grounded battery, through the left-hand winding of relay 421, lowercontacts of sequence switch spring 415 (9), resistance element 425,upper contact of sequence switch spring 404 (1+10), thence over thefundamental circuit as previously traced and returning through the lowercontact of sequence switch spring 403 (1+10), resistance element 424,contacts of sequence switch spring 408 (9), and thence to ground throughthe upper contacts of sequence switch spring 412. Y

The current now flowing over the fundamental circuit is in such adirection as to energize both the sender stepping relay 521 and theoverflow relay 522. Overflow relay 522, upon energizing, establishes acircuit for the advance relay 537, which, at its armature and backcontact, opens the previously traced circuit through the winding of callcharging relay 365. Relay 365 thereupon deenergizes opening the circuitof relay 327, which thereupon deenergizes and establishes the previouslytraced circuit for driving sequence switch 300 of the district selectorout of position 9 and into, position 10. With sequence switch 300 inposition 10, a circuit is now established from grounded battery, throughthe lefthand winding of relay 327 of the district selector switch, lowerleft-hand contactof sequence switch spring 310 (10), upper lefthandcontact of said spring (10+13),'front contact and outer left-handarmature of relay 325, wiper 350 and contact 383 of the sender finderFS, upper and lower contacts of sequence switch spring 519 (16),armatureand back contact of the No. 0' counting relay 520, winding of overflowrelay 522 and sender stepping relay 521, and thence to ground throughthe lower contacts of se uence switch spring 523 (1 Relays 32 and 521energize in this c1rcuit, the relay 521 establishing a circuit for thelower counting relay for controlling the subse-v quent movement of'thesequence switch 300 of the district selector for controlling talkingselection. In this case it will be assumed that the No. 0 counting relayhas been prepared for operation through the setting of code registers bythe calling subscriber.

Upon the movement of sequence switch 300 out of position 9 the impulsingcircuit over which the calling subscriber set the registers of theofiice sender is opened at contacts of sequence switch springs 312 and313, and the talking conductors of the district selector trunk are nowconnected over contacts of these springs to wipers 242 and 243 of thesteeringv switch RS. Sequence switch 300, upon reaching position 9%,establishes a circuit for advancing the steering switch RS from position2 to position 3.

This circuit may be traced from grounded battery through the backcontact and armature and winding of stepping magnet 230, wiper 231, theposition 2 contact upon which it is now standing, conductor 233, andthence to ground through the upper left-hand con i the wiper 266, wiper266, conductor 248, lower left-h and contact of sequence switch spring380 (10), upper right-hand contact of said spring (2+18) to ground. Theresistance of the right-hand winding of relay 244 is so selected that ifrelay 249 energizes in series therewith. relay 249 will consequentlyenergize over the line resistance of any calling subscribers line towhich it may be later connected in testing for a discriminatorycondition upon such subscribers line. If relay 249 energizes, a circuitis immediately closed for energizing relay 252, which circuit may betraced from grounded battery, through the right-hand winding of relay252, .front contact. and outer left-hand armature of relay 224, "andthence to ground at the armature and front contact of relay 249. Relay252, upon energizing, establishes a circuit for advancing the steeringswitch out of position 3 and into position 4, this circuit extendingvirom grounded battery, through the back contact, armature and windingof stepping magnet 230, wiper 231, the third position contact upon whichit is resting, and thence to ground at the outer right-hand armature andfront contact of relay 252. Relay 252 performs no other use ful functionat this time. As soon as the steering switch leaves position 3, thecircult of relay 249 is opened and relays 249 and 252 release.

If the test relay 249 fails to energize when connected to the right-handwinding of relay 224 upon the routine test to determine thesensitivenessof relay 249, then the steering switch remains in position 3 and relay224 is maintained energized for a sufiicient time to connect groundthrough its outer left-hand armature and front contact to thecircuitextending to the selector time alarm for causing the selectortime alarm to operate.

W'hen the steering switch reached position 3, a circuit was establishedfor the answering supervisory relay 370, which may be traced fromgrounded battery, through the lower left-hand winding of repeating coil336, winding of relay 370, conductor 371, wiper 243 of the steeringswitch and its third position contact, and thence to ground through theright-hand non-inductive winding of relay 222. This circuit ismaintained through position 9 of the steering switch. Relay 370, uponenergizing, establishes a holding circuit for the slow-to-release relay390 extending from grounded battery through i the right-hand winding ofrelay 390, frontv contact and armature of relay 370, right-hand armatureand alternate contact of relay 390, and thence to ground through thelower left-hand contact of sequence switch spring 314 (l 448 4 The abovetraced locking circuit holds relay 390 operated after its initialenergizing. circuit through the upper left-hand contact'of sequenceswitch spring 314 (1+10 is opened as the sequence switch 300 is advancedbeyond position 10.

When relay 252 deenergizes, a circuit for moving the steering switchfrom position 4 to position 5 is 5. completed as follows: groundedbattery, back contact, armature and'winding of magnet 230, wiper 231 andthe fourth position contact with which it is associated, back contactand outer righthand armature of relay 252 to ground.

When the wipers of the steering switch reach position 5,3 circuit isestablished for the stepping magnet 230 extending from grounded battery,through the fifth position contact of wiper 247, wiper 247, the windingof magnet 230, wiper 231 and the fifth position contact upon which it isresting, and to .ground at the contact controlled by interrupter cam 254for advancing the steering switch from position 5 to position 6, as soonas the cam 254 makes and interrupts its contact. Upon reaching position6, the circuit of magnet 230 is again established through the contact ofcam 254 and the switch continues to advance under the control of cam 254into position 8. Upon reaching position 8, a circuit is established formagnet 230 extending from grounded battery, through the eighth positioncontact of the switch wiper 247, magnet 230, Wiper 231 and the eighthposition contact upon which it is resting, conductor 233, and thence toground through the upper left-hand contact of ,sequence switch spring389 (9 14-10 1,). The magnet is held energized over this circuit anddoes not advance the wipers of the steering switch from position 8 untilsequence switch 300 leaves position 10 During the time that the steeringswitch is advancing through positions 3 to 6, inclusive, the tipconductor of the subscribers line is connected to grounded battery forthe purpose of' removing any charge that may have accumulated on theline and which might later erroneously affect the testing circuitestablished; through the testing relay 249. This circuit may be tracedfrom conductor 116 through the lower right-hand contact of sequenceswitch spring 312 (9%+13 conductor 372, Wiper 242, contacts 3 to 6 overwhich this wiper passes, to grounded battery. When the steering switchreaches position 7, the winding of the test relay 249 is connected tothe tip conductor of the subscribers line, and if, as in the caseassumed, the subscriber at substation 7: A of the calling line hasinitiated the call, the relay 249 will energize over a circuit? whichmay be traced from grounded battery, through the winding of relay 249,the seventh position contact as sociated with the wiper 242, wiper 242,con. ductor 372, lower right-hand contact of sequence switch's'pring 312(9 44-13 4;), trunk conductor 116. back contact and intermediateleft-hand armature of relay 292, brush 204, contact 200, primary windinof the substation repeating coil 128, switchhook contact 129 and thenceto ground through the subscribers call bell 131. Relay 249 energizes inthis circuit and as relay 224 is at this time deenergized, establishes acircuit for the switching relay 222 which may be traced from groundedbattery, through the lefthand winding of relay 222, conductor 256, frontcontact and outer left-hand armature of relay 394, back contact andouter lefthand armature of relay 224, and thence to ground through'thearmature and front contact of relay 249. Relay 222 energizes in thiscircuit and establishes a locking circuit for itself extending fromgrounded battery, through its left-hand winding, front contact andleft-hand armature, and lower left-hand contact of sequence switchspring 314 (l 4 18 4), to ground. The previously traced circuit for testrelay 249 is main tained through wiper 242 of the steering switch untilthe steering switch leaves position 8.

With the wipers 'of the steering switch standing on their eighthposition contacts, a

circuit is established for advancing the se-' quence switch 300 of thedistrict selector out of position 10. This circuit may be traced fromgrounded battery through the magnet winding of sequence switch 300,lower righthand contact of sequence switch spring 306 10+l3), frontcontact and outer right-hand armature of relay 327, (the relay 327 beingmaintained energized at this time over the fundamental circuit extendingthrough the sender stepping relay 521), eighth position contact uponwhich wiper 266 of the steering switch is now resting, wiper 266,conductor 248, lower left-hand contact of sequence switch spring 380(10), and upper right-hand contact of said sequence switch spring (2+18)to ground. Upon reaching position 11, the circuit for advancing thesequence switch is maintained over the righthand contacts of sequenceswitch spring 307 and the switch advances through the succes siretalking selection positions. Relay 327 is maintained energized inposition 11 of sequence switch 300 by a circuit from grounded battery,through its left-hand winding, armature and front contact, lower rightcontact of spring 310, (UH-17), upper leftcontact of 310 (10+13) outerleft-hand contact of relay 325 and thence to ground over the fundamentalcircuit.

As soon as the sequence switch 300 leaves posit-ion 10 the previouslytraced energizing circuit of stepping magnet 230 of the steering switchis opened and the magnet 230 advances the wipers of the steering switchout of position 8 and into position 9. In position 9, a circuit isestablished from grounded battery through the armature, contacts andwinding of stepping magnet 230, wiper 231, to ground on the ninthposition contact upon which it is resting for advancing the wipers ofthe steering switch over the ninth position into position 10. Inposition 10, the trunk conductors 116 and 117 are connected through thewipers 242 and 243 of the steering switch to conductors 372 and 371, andthe answering supervisory relay 370 is now maintained energized over thecalling subscribers loop.

As the district selector 300 passes through position 10%, a shuntcircuit is established in shunt of the windings of the sender steppingrelay 521, which may be traced from grounded battery, through theleft-hand winding, left-hand armature and front contact of relay 327,lower left-hand contact of sequence switch spring 315 and to ground atthe upper left-hand contact of sequence switch spring 315 (7%-|-13 Relay327 is maintained in this circuit but the sender stepping relay 521becomes deenergized and in the well-known manner causes the energizationof the upper counting relay corresponding to the lower counting relaywhich was energized upon the initial energization of sender steppingrelay 521 in the talking selection position (16) of the sender sequenceswitch 550. Since, in the case assumed, the No. 0 counting relay 525 wasthus initially energized, the No. 0 counting relay 520 now energizes andopens the fun.- damental circuit at its armature and front contact.

The energization of the No. 0' counting relay 520 causes relay 327 tobecome deenergized since its locking circuit is now open. Relay 327,upon deenergizing, opens the driving circuit of sequence switch 300 andthe sequence switch is arrested upon reaching position 11.

After sequence switch 300 leaves position 10, relay 325 is maintainedenergized to maintain the fundamental circuit closed through the windingof relay 327 until it is interrupted by the No. 0 counting relay of theofiice sender over a circuit which may be traced from grounded batterythrough the right-ham] winding of relay 325, upper right-hand contact ofsequence switch spring 316 (104-13), front contact and right-handarmature of relay 394, upper right-hand contact of sequence switchspring 333 (10+15), front contar t and inner righthand armature of relay327, lower righthand contact of sequence switch contact 315 (1+14),upper left-hand contact of sequence switch spring 315 (7%+13 to ground.As soon as the talking selection is completed and relay 327 deenergizesas above described, this holding circuit for relay 325 is opened andrelay 325 deenergizes, thereby opening the circuits controlled thereby.At the oflice sender upon the opening of the fundamental circuit thesequence switch of the oflice sender is driven into normal position andthe circuits of the sender are restored to normal in the well-knownmanner.

Upon the setting of the sequence switch 300 of the district selectorswitch into its talking selection position, the incoming selector switchfunctions to apply ringing currentand when the called subscriber answersrelay 421 deenergizes whereupon the ringing current is disconnected fromthe called line and the sequence switch 400 is driven from position 14to 16, all as described in the aforementioned patent to Taggart andSend- As soon as sequence switch 400 reaches position 14, a directcurrent path is established through the right-hand winding of repeatingcoil 458, and thence over the called subscribers line for supplying thecalled subscribers line with talking current. This path may be tracedfrom grounded battery through the lower right-hand winding of repeatingcoil 458, winding of supervisory relay 459, contact of sequence switchspring 414 (14+16), brush 448 and terminal 449 of the incoming selectorswitch, brush 480, and terminal 482 of the final selector switch, thencethrough the called subsrribers substation loop, terminal 486 and brush484 of the final selector switch, terminal 447 and brush 446 of theincoming selector switch, contact of sequence switch spring 413(13%+16), and thence to ground through the upper right-hand winding ofrepeating coil 458. Supervisory relay 459 energizes in this circuit andconnects the terminals of the central station battery between thelefthand windings of repeating coil 458 in such a manner as to causecurrent to flow over the trunk line incoming through the selector switchand the district selector switch in such a manner as to energize thepolarized call charging relay 374 at the district selector switch toclose its alternate contact. This circuit may be traced from groundedbattery over conductor 460, through the upper contact of sequence switchspring 405 (11+16), conductor 426. resistance element 425, uppercontacts of sequence switch spring 415 (11'to 16), lower left-handwinding of repeating (oil 4.58, lower contact of sequence switch spring404 (11-1-16). trunk conductor 420, contact 356 and brush 352 of thedistrict selector switch, upper right-hand contact of sequence switchspring 319 (9-1-14), lower left-hand contact of sequence switch spring319 (114-13 4). lower righthand winding of repeating coil 336, upperleft-hand contact of sequence switch spring 396 (10+11 winding ofpolarized relay 374, upper right-hand contact of sequence switch spring395 (104-13 4), up-

per left-hand contact of sequence switch spring 395 (10+11 upperright-hand winding of repeating coil 336, upper lefthand contact ofsequence switch spring 31% (114-13 1;), upper right-hand contact of sequence switch spring 318 (9+14), brush 351 and contact 355 of thedistrict selecto switch, trunk conductor 419, upper contac of sequenceswitch spring 403 (11+16), upper left-hand winding of repeating coil458. resistance 424, and thence through the armature and contact ofsupervisory relay 459 t ground.

The calling and called subscribers are now connected over a't-alkingcircuit with each other, shown on the drawing by heavy lines, thecalling subscriber receiving current over the circuit previously tracedthrough the left-hand winding of repeating coil 336, and the calledsubscriber receiving current over the repeating coil 458.

Upon the energization of polarized relay 374 with the sequence switch300 of the district selector in talking position 11, a circuit isestablished for relay 252 as soon as interrupter earn 259 rotates tosuch a position as to close contacts 260. This circuit may be tracedfrom grounded battery, through the left-hand winding of relay 252,contacts 260, conductor 261, upper and lower righthand contacts ofsequence switch spring 324 (11+12), alternate contacts of polarizedrelay 374 and upper right-hand contact of sequence switch spring 314(11+13 to ground. Relay 252, upon energizing, locks up through itsleft-hand winding and outer left-hand contacts to conductor 261, and atits inner left-hand armature prepares a circuit for the call chargingrelay 365 which is closed upon the advance of the interrupter cam 259 toa position in which its contacts 260 are opened and its contacts 262 areclosed. This circuit may be traced from grounded battery, through theright and left-hand windings of relay 365, contacts 262. front contactand inner left-hand armature of relay 252, outer left-hand armature andfront contact of relay 252, and thence to ground on conductor 261. Relay365, upon energizing in this circuit, closes a locking circuit foritself extending through its windings, lower right-hand and upperleft-hand contacts of sequence switch earn 305, and to ground at theouter right-hand contacts of relay 365. At its innermost right-handarmature, relay 365 prepares a circuit for charging a call on thecalling partys message register as soon as the calling arty restores thereceiver to the switchhoo to release the established connection.

Following the termination of the conversation, both the calling andcalled subscribers restore their respective receivers to theirswitchhooks and the circuit previously traced through the answeringsupervisory relay 370 is opened at the switchhook contacts at thecalling subscribers station. This relay upon deener'gizing opens thelockneensee I ing circuit of slow to release relay 390, which, after aninterval, closes a circuit for driving, sequence switch 300 out ofposition 11 into position 16. This circuit may be traced from groundedbattery, through the winding of sequence switch magnet 300. lowerleft-hand and upper left-hand contacts of sequence switch spring 323(11+15), right hand normal contacts of relay 390 and lower left-handcontacts of sequence switch spring 314 (l 448 1,) to ground. Upon thedeenergization of relay 390, the circuit previously traced extendingthrough the windings of sleeve relay 398 is opened at the left-handalternate contacts of relay 390 and relay 398 thereupon releases.

en sequence switch 300 reaches position 13, a circuit is established tothe stepping magnet 230 of the steering switch RS for advancing thewipers of the steering switch from position 10 into position 11, whichcircuit may be traced from grounded battery through the 10th positioncontact, upon which wiper 247 is resting, wiper 247, winding of steppingmagnet 230, wiper 231 and the 10th position contact upon which thiswiper is standing, conductor 233, and thence to ground at the upperleft-hand contact of sequence switch spring 389 (13+13 This circuit ismaintained until the' sequence switch leaves position 13% when steppingmagnet 230 deenergizes, advancing the wipers to position 11. In position11, the talking circuit extending through Wipers 242 and 243 is stillmaintained in order that a tone signal may be transmitted to the callingsubscriber in case the district selector switch had failed to find anidle trunk extending to an incoming selector switch and had thereforemoved to its overflow position. This operation of the district selectorwill be described hereinafter. When sequence switch 300 passes intoposition 14%, the previously traced circuit for magnet 230 is againestablished and when the sequence switch leaves position 15 1; thestepping magnet 230 advances the wipers of the steering switch fromposition 11 to 12, where, under the control of the contact of theinterrupter 254, stepping magnet advances the wipers of the steeringswitch to position 16.

While the wipers of the steering switch are (passing over positions 12and 13, the tip con uctor of the calling subscribers line is connectedover the wiper 242, to grounded battery to discharge the subscribersline and, when passing over positions 14 to 16, the testing relay 249 isagain connected to the tip conductor of the calling line to test for anunsta-ndard condition of the line. If the calling line is in a standardcondition, no ground is connected at this time, since the callingsubscriber has restored his receiver to the switchhook and has thereby 7this time.

disconnected the ground connection through the call bell 131, aspreviously described. If, however, the line is in an unstandardcondition and either the ringer tip conductors are permanently connectedto ground through a stray ground connection, the test relay 249 willbecome energized at In order that the test may be made both on the tipand ring conductors, theyare bridged together at this time over acircuit extendin from conductor 116 through the lower right-hand contactof sequence switch spring 312 (14 4-1-17). lefthand contacts of chargingrelay 365 and thence to conductor 1.17 through the lower right-handcontact of sequence switch spring 313 (16).

If the test relay 249 operates on this second test, a holding circuit isestablished for relay 252 for maintaining this relay energized when thesteering switch reaches position 16. Relay 252 is operated over a localcircuit while the steering switch was passing from position 9 to 15which may be trace from grounded battery, through its righthand winding,contacts 9 to 15 over which the wiper 266 passes, wiper 266. conductor248 and thence to ground through the lower left-hand contact of sequenceswitch spring 380 (15 to 18) and upper right-hand contact of said spring(2+18) to ground. The

' holding circuit for relay 252 may be traced from grounded battery.through its righthand winding, outer left-hand armature and frontcontact of relay 224 and thence to ground at the armature and frontcontact of relay 249. )Vith relay 252 operated when the steering switchRS reaches position 16, the steering switch is arrested in position 16and the circuit is established to the selector time alarm extending fromground on conductor 248, wiper 266, the 16th position contact upon whichthe wiper rests and over conductor 264 to the selector time alarm.

The operation of the selector time alarm warns the switchboard attendantthat an unstandard condition obtains on a connection that has beenestablished through the particular district selector switch with whichthe time alarm is associated. The operation of relay 249 at this timeprevents the registration of the call upon the message register ofeither of the parties on the calling line, and therefore prevents theregistration of a call on the register of the party A when the party Amay not have been the calling arty. 1

If the test relay 249 does not operate on the second test, relay 252will not be held energized when the steering switch reaches position 16and the steering switch will, therefore, be advanced out of position 16by a circuitextending from grounded battery, through the back contact,armature and winding of stepping magnet 230, wiper 231,

the wipers of the steering switch have reached position 17 they areadvanced into position 20 through the operation of interrupter cam 254in the manner previously described.

As the steering switch RS passes through positions 17 18 and 19 and withrelay 222 operated as previously described, relay 296 will be shunteddown by. a path including grounded battery, resistance 250, innerright-hand contacts of relay 222, 17th, 18th and 19th position contactsa of wiper 266, wiper 266, conductor 284, lower left-hand contact ofsequence switch spring 380 (15+18) and ground at the upper right-handcontacts of said spring (2+18), causing the-release of relay 398 and thecut-off relay 103, associated with calling subscribers line. The circuitfor operating the message register associated with the callin line isthen completed over a path extending from ground, through the messageregister magnet 123, back contact and outer right-hand armature of relay103, back contact and outer righthand armature of relay 102, contact 203and brush 207, resistance 297, contacts of relay 279,- outer right-handalternate contacts of relay 222, inner right-hand normal contact ofrelay 252, lower left-hand contact of sequence switch spring 381 (16),upper lefthand contact of said spring (11-1-16), and inner light-handcontacts of charging relay 365 to grounded battery. The message registernow operates in a manner well known in the art and registers a callagainst the calling party A.

If station B had been the calling station, relay 249 and consequentlyrelay 222 would not have energized in position 7 of the steering switchRS. Relay 296 will not be shunted down in positions 17, 18 and 19 of thesteering switch and relay 398 will remain operated. The circuit formaintaining relay 398 operated includes grounded battery at the innerright-hand contacts of relay 365, upper left-hand contacts of sequenceswitch spring 381 (11-1-16), winding of relay 398, outer left-handcontacts of relay 296, righthand normal contacts of relay 299. segment284 and ground at brush 281. Since relay 398 is held at this time, relay103 remains operated. The circuit for operating the message register maybe traced :trom ground, through the message register 144, front contactand right-hand armature of relay 103,

outer armature and back contact of relay 102, contact 203, brush 207,resistance 297, outer right-hand normal contacts of relay .222, innerright-hand contacts of relay 252,

lower left-hand contacts of sequence switch spring 381 (16). upperleft-hand contacts of said spring and inner right-hand contacts of relay365 to grounded battery. The message register then operates inla mannerwell known in the art and registers a call'againsi' the station B. 7

During the advancement of the wipers of the steering switch from sition16 to 20, this battery is supplied or operating the message register,the movement of the steering switch leaving suflicient time for theoperation of the registers. When the steering switch reaches position20, a circuit is established for advancing sequence switch 300 out ofposition 16 into position 17, said circuit extending over a path fromgrounded battery, through the winding of sequence switch magnet 300,lower left-hand contact of sequence switch spring 306 (16), back contactand outer right-hand armature of relay 327, 20th position contactassociated with wiper 266, wiper 266, lower left-hand contact ofsequence switch spring .380 (15+18), and upper right-hand contact ofsaid spring (2+18) to ground. In position 17, the sequence switclr300isadvanced to position 18 under control of spring301. Withsequence-switch 300 in position 18, a circuit is established foradvancing the steering switch into position 21, which circuit may betraced from grounded battery, through the back contact, armature andwinding of the stepping magnet 230, wiper 231, the twentieth positioncontact with which it is associated, lower right-hand contact ofsequence switch 323 (18), upper lefthand contact of said spring (118)right-hand normal contacts of relay 390, thence to ground to the lower:left-hand contact of sequence switch spring 314 (1 448 4).

With sequence switch 300 in position 18 and the steering switch inposition 21, a air cuitis now established for the downdrive magnet 376of the district selector switch, which may be traced from groundedbattery, through the winding of magnet 376, conductor 377, the 21stposition contact with which wiper 266 is in engagement, wiper 266,conductor 248, lower left-hand contact of sequence switclrspring 380(15+18) and upper right-hand'contact of said spring (2+18) to ground.The down-drive magnet 3T6 upon being energized, presses the dependingportion aof the switch shaft, not shown, against the constantly rotatingdown-drive drum, not shown, whereby the switch shaft is drivendownwardly into the normal position in a manner well known. WVhen theswitch shaft. reaches its normal position, the brnsh 360'engages thenormal segment 379 of the switch commutator and a circuit is establishedfor advancing the steering switch into position 22. This circuit may betraced from battery through the armature, contact and. winding of magnet230. wiper 231, 21st position contact with which the wiper 231 is inengagement, 21st menses position contact with which the'wiper 291 is inengagement, normal segment 379, brush 360, conductor 344, and thence toground through the lower right-hand contact of sequence switch 314(8+6); In position 22, an obvious circuit is completed through wiper 231for driving the steering switch into. normal position. With the steeringswitch in normal position, a circuit is now established for drivingsequence switch 300 into normal position which may be traced fromgrounded battery, through the magnet winding of sequence switch 300,upper righthand contact of sequence switch spring 306 (4+18), the normalor No. 1 contact with which wiper 291 of the steering switch is inengagement, wiper 291, normal segment 379, brush 360, conductor 344 andthence to ground through the lower right-hand contact of sequence switchspring 314 (8+6).

and with relay 390 deenergized, a circuit for relay 27 0 was completedover a path extendin from grounded battery, through the left-hand normalcontacts of relay 27 0, through the left-hand normal contacts of relay390, lower and upper lefthand contacts of sequence switch 324 (17-1-18),left-hand winding of relay 270, segment 284 of the switch LF and brush281 to: ground. Relay 270, in operating, starts the down-drive of theline finder switch LF. Relay 270, in attracting its outer right-handarmature coinpletcs an obvious circuit through the lefthand winding ofrelay 292 causing the energization of said relay 292. Relay 292, inoperating, holds the tip and ring talking conductors 116 and 117 openduring the down-drive. When the commutator brushes 280 to 282 inclusiveof the switch LF are returned to normal position, the circuits forrelays 270 and 296 are opened causing the release of said relays.

As the sequence switch 300 leaves position 18 the circuit for relay 298is opened at the lower lefteha-nd contacts of sequence switch spring 314(l 448 1;) and if relay 296 is released at the end of the down-drivemovement of the line finder, relay 298 will become deenergized.

As soon as sequence switch 300 of the district selector switch leavesposition 14, the circuit for the relay 421 associated with the incomingselector switch is opened,

whereupon said relay 421 releases and causes the restoration of theincoming selector to normal, after which the final selector is restoredto normal in the manner described in the aforementioned Taggart etalcpatcnt.

WVith sequence. switch 300 in position 18 comes deenergized, opening thecircuit of up-drive magnet 338 and establishes the previously tracedcircuit for driving the sequence switch 300 out of position 7 and intoposition 8. In position 8, relay 327 becomes energized over a localcircuit extending from grounded battery, through its righthand winding,upper left-hand contact sequence switch spring 304 (8+9), upperright-hand contact of sequence switch spring 305 (1+9), upper left-handcontact of said s ring (8+16 A), and the outer right-han contacts ofrelay 365 to ground, and closes at its outer right-hand armature andfront contact, a circuit for driving sequence switch 300 out of position8 and into position 9. In position 9, relay 327 is maintained energizedover the previously traced circuit. A circuit is now established fordriving sequence switch 300 out of position 9 to position 10 whichcircuit may be traced from grounded battery, through sequence switchmagnet 300, lower left-hand sequence switch spring 311 (9), upperleft-hand con tact of spring 311 (9+13), conductor 343, commutatorsegment 342, brush 341, conductor 344, and thence to ground through thelower right-hand contact of sequence switch spring 314 (8+6). Whensequence switch 300 reaches position 10, a circuit is established forrelay 327 which is traced from grounded battery, through the lefthandwinding of relay 327,1ower left-hand contact of sequence switch spring310 (10), upper left-hand contact of sequence switch spring 311 (9+13),conductor'343, commutator segment 342, brush 341, conductor'344 andthence to ground through the lower right-hand contacts of sequenceswitch.

spring 314 (8+6). The steering switch has at this time positioned itswipers on the No. 8 contacts of its banks in the manner previouslydescribed and a circuit is established through the outer right-handarmature and front contact of relay 327 for driv-- ing sequence switch300 out of position 10. When the sequence switch leaves position 10. theenergizingcircuit of relay 327 previously traced is opened at the lowerlefthand contact'of sequence switch spring 310 but relay 327 ismaintained locked up over its left-hand armature and front contact, thelower right-hand contact of sequence switch spring 310g(10+17), upperlefthand contact of spring 311 (9+13), conductor 343, segment 342, brush341, to ground at the contact of sequence switch spring 314 (8+6), untilthe sequence switch advances into position 14 when the circuit of relay327 is opened and relay 327, upon deenergizing, closes a circuit fordriving sequence switch 300 into position 15. This circuitmay be tracedfrom grounded battery. through the magnet winding of sequence switch300, lower left-hand contact of sequence switch spring 306 (14) backcontact and outer right-hand armature of relay 327 and thence to groundthrough the upper right-hand contact of sequence switch spring 307(11+15).

As previously described, when sequence switch 300 passes out of position10, the steering switch RS advances to position 10, the talkingposition, and as sequence switch 300 passes out of position 13% thesteering switch BS is further advanced to position 11. Since now thedistrict selector switch has moved to its overflow position and thesequence switch 300 is standing in position 15, a circuit is establishedfor applying tone current to the right-hand winding of repeating coil336 from the source of tone current 368, through the left-hand contactsof sequence switch spring 319 (15), lower right-hand winding ofrepeating coil 336, condenser 399, lower left-hand contact of spring 395(15), upper left-hand contacts of spring 333 (14+15), upper right-handcontact of said spring (10+15), lower righthand contact of spring 382(15+18), upper left-hand contacts of said spring (13+15), right-handalternate contacts ofrelay 390 and lower left-hand contact oi sequenceswitch spring 314 (l +1 8 to ground.

This tonecurrent is inductively transmitted over the calling subscribersline through the left-hand windings of repeating coil 336, thesupervisory relay 370 and the wipers 242 and 243 of the steering switch.The calling subscriber receiving this tone is apprised of the fact thatit is impossible to obtain the desired connection at this time andtherefore restores his receiver to its switchhook to release theconnection.

What is claimed is:

1. In a telephone exchange system, a calling telephone line, a pluralityof stations thereon, a message register for each station of the line,automatic switching means for extending a connection from the callingline, a circuit for operating the message registers, means common to aplurality of lines for testin the calling line to determine whichstation of the party line is calling, a switching device individual tothe calling line controlled by said testing means for extending saidcircuit to the message register corresponding to the calling line, and;means for closing said message register circuit to actuate saidregister.

2. In a telephone exchange system,a calling telephone line, a pluralityof stations thereon, a message register for each station of the line,automatic switching means for extending a connection from the telephoneline, a circuit for operating the message registers, means common to aplurality of lines for testing the calling line to determine whichstation of the party line is calling, electromagnetic means individualto the

